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<div class="titlepage"><div><div><h4 class="title">
<a name="fusion.iterator.metafunctions.deref_data"></a><a class="link" href="deref_data.html" title="deref_data">deref_data</a>
</h4></div></div></div>
<h6>
<a name="fusion.iterator.metafunctions.deref_data.h0"></a>
          <span class="phrase"><a name="fusion.iterator.metafunctions.deref_data.description"></a></span><a class="link" href="deref_data.html#fusion.iterator.metafunctions.deref_data.description">Description</a>
        </h6>
<p>
          Returns the type that will be returned by dereferencing the data property
          referenced by an associative iterator.
        </p>
<h6>
<a name="fusion.iterator.metafunctions.deref_data.h1"></a>
          <span class="phrase"><a name="fusion.iterator.metafunctions.deref_data.synopsis"></a></span><a class="link" href="deref_data.html#fusion.iterator.metafunctions.deref_data.synopsis">Synopsis</a>
        </h6>
<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span>
    <span class="keyword">typename</span> <span class="identifier">I</span>
    <span class="special">&gt;</span>
<span class="keyword">struct</span> <span class="identifier">deref_data</span>
<span class="special">{</span>
    <span class="keyword">typedef</span> <span class="emphasis"><em>unspecified</em></span> <span class="identifier">type</span><span class="special">;</span>
<span class="special">};</span>
</pre>
<div class="table">
<a name="fusion.iterator.metafunctions.deref_data.t0"></a><p class="title"><b>Table 1.21. Parameters</b></p>
<div class="table-contents"><table class="table" summary="Parameters">
<colgroup>
<col>
<col>
<col>
</colgroup>
<thead><tr>
<th>
                  <p>
                    Parameter
                  </p>
                </th>
<th>
                  <p>
                    Requirement
                  </p>
                </th>
<th>
                  <p>
                    Description
                  </p>
                </th>
</tr></thead>
<tbody><tr>
<td>
                  <p>
                    <code class="computeroutput"><span class="identifier">I</span></code>
                  </p>
                </td>
<td>
                  <p>
                    Model of <a class="link" href="../concepts/associative_iterator.html" title="Associative Iterator">Associative
                    Iterator</a>
                  </p>
                </td>
<td>
                  <p>
                    Operation's argument
                  </p>
                </td>
</tr></tbody>
</table></div>
</div>
<br class="table-break"><h6>
<a name="fusion.iterator.metafunctions.deref_data.h2"></a>
          <span class="phrase"><a name="fusion.iterator.metafunctions.deref_data.expression_semantics"></a></span><a class="link" href="deref_data.html#fusion.iterator.metafunctions.deref_data.expression_semantics">Expression
          Semantics</a>
        </h6>
<pre class="programlisting"><a class="link" href="deref_data.html" title="deref_data"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">deref_data</span></code></a><span class="special">&lt;</span><span class="identifier">I</span><span class="special">&gt;::</span><span class="identifier">type</span>
</pre>
<p>
          <span class="bold"><strong>Return type</strong></span>: Any type
        </p>
<p>
          <span class="bold"><strong>Semantics</strong></span>: Returns the result of dereferencing
          the data property referenced by an associative iterator of type <code class="computeroutput"><span class="identifier">I</span></code>.
        </p>
<h6>
<a name="fusion.iterator.metafunctions.deref_data.h3"></a>
          <span class="phrase"><a name="fusion.iterator.metafunctions.deref_data.header"></a></span><a class="link" href="deref_data.html#fusion.iterator.metafunctions.deref_data.header">Header</a>
        </h6>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">iterator</span><span class="special">/</span><span class="identifier">deref_data</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">deref_data</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
</pre>
<h6>
<a name="fusion.iterator.metafunctions.deref_data.h4"></a>
          <span class="phrase"><a name="fusion.iterator.metafunctions.deref_data.example"></a></span><a class="link" href="deref_data.html#fusion.iterator.metafunctions.deref_data.example">Example</a>
        </h6>
<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">map</span><span class="special">&lt;</span><span class="identifier">pair</span><span class="special">&lt;</span><span class="keyword">float</span><span class="special">,</span> <span class="keyword">int</span><span class="special">&gt;</span> <span class="special">&gt;</span> <span class="identifier">map_type</span><span class="special">;</span>
<span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">fusion</span><span class="special">::</span><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">begin</span><span class="special">&lt;</span><span class="identifier">map_type</span><span class="special">&gt;::</span><span class="identifier">type</span> <span class="identifier">i_type</span><span class="special">;</span>
<span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">fusion</span><span class="special">::</span><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">deref_data</span><span class="special">&lt;</span><span class="identifier">i_type</span><span class="special">&gt;::</span><span class="identifier">type</span> <span class="identifier">r_type</span><span class="special">;</span>
<span class="identifier">BOOST_STATIC_ASSERT</span><span class="special">((</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">is_same</span><span class="special">&lt;</span><span class="identifier">r_type</span><span class="special">,</span> <span class="keyword">int</span><span class="special">&amp;&gt;::</span><span class="identifier">value</span><span class="special">));</span>
</pre>
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<td align="right"><div class="copyright-footer">Copyright © 2001-2006, 2011, 2012 Joel de Guzman,
      Dan Marsden, Tobias Schwinger<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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